leetcode

Solution to some Leetcode problems written in C++
git clone git://git.dimitrijedobrota.com/leetcode.git
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commit9eb5c5a876e83fa6ddda352dd4a9f06a947ba20b
parent221c3920e85e34f3fddec4c2310318ee286f1751
authorDimitrije Dobrota <mail@dimitrijedobrota.com>
dateWed, 10 Jan 2024 22:38:44 +0000

1 Random Problem

Diffstat:
AProblems/1911.cpp|++++++++++++++++++++++++++++++++++++++++++
MREADME.md|+

2 files changed, 43 insertions(+), 0 deletions(-)

diff --git a/Problems/1911.cpp b/Problems/1911.cpp

@@ -0,0 +1,42 @@

// Standard dp
class Solution {
static long long dp[2][100001];
long long rec(const vector<int> &nums, const int crnt, const bool odd) {
if (crnt >= size(nums)) return 0;
if (dp[odd][crnt] != -1) return dp[odd][crnt];
long long res =
max(rec(nums, crnt + 1, odd), (odd ? -1 : 1) * nums[crnt] + rec(nums, crnt + 1, !odd));
return dp[odd][crnt] = res;
}
public:
Solution() { memset(dp, 0xFF, sizeof(dp)); }
long long maxAlternatingSum(const vector<int> &nums) { return rec(nums, 0, 0); }
};
long long Solution::dp[2][100001];
// Optimized 1
class Solution {
public:
long long maxAlternatingSum(const vector<int> &nums) const {
long long odd = 0, even = 0;
for (const int n : nums) {
even = max(even, odd + n), odd = even - n;
}
return even;
}
};
// Optimized 2
class Solution {
public:
long long maxAlternatingSum(const vector<int> &nums) const {
long long res = nums[0];
for (int i = 1; i < size(nums); i++) {
res += max(nums[i] - nums[i - 1], 0);
}
return res;
}
};

diff --git a/README.md b/README.md

@@ -874,6 +874,7 @@ for solving problems.

| 1905 | Medium | [Count Sub Islands](Problems/1905.cpp) |
| 1907 | Medium | [Count Salary Categories](Problems/1907.cpp) |
| 1910 | Medium | [Remove All Occurrences of a Substring](Problems/1910.cpp) |
| 1911 | Medium | [Maximum Alternating Subsequence Sum](Problems/1911.cpp) |
| 1913 | Easy | [Maximum Product Difference Between Two Pairs](Problems/1913.cpp) |
| 1921 | Medium | [Eliminate Maximum Number of Monsters](Problems/1921.cpp) |
| 1926 | Medium | [Nearest Exit from Entrance in Maze](Problems/1926.cpp) |